def del_node(node):
    if not node or not node.next:
        raise Exception('非法输入')
    node.val = node.next.val
    node.next = node.next.next

from utils import list12345, node2, node3, node4, node5, print_list
print_list(list12345)
del_node(node3)
print_list(list12345)
